Magpies are an exception to this and will target nests but will also attack smaller birds, kill and eat them.

One bird was less fortunate. A local shopowner described to me the dismantling of a blackbird by a magpie on the pavement in front of his shop and also how all the songbird nests in a regular nesting site in the tall trees at the bottom of his garden had seen their eggs and nestlings destroyed by magpies.
Their numbers in our locality are huge - so the damage being done is inestimable.Come on the RSPB. A cull is overdue!